The End of Time
The End of Time
The Next Revolution in Physics
Julian Barbour
Oxford New York
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Copyright © 1999 by Julian Barbour
First published by Oxford University Press, Inc., 1999
First issued as an Oxford University Press paperback, 2001
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Oxford is a registered trademark of Oxford University Press
All rights reserved. No part of this publication may be reproduced,
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Library of Congress Cataloging-in-Publication Data
Barbour, Julian B.
The end of time: the next revolution in our
understanding of the universe/by Julian Barbour.
p. cm.
Includes bibliographical references and index.
ISBN-13 978-0-19-511729-5; 978-0-19-514592-2 (pbk.)
1. Space and time. 2. Relativity (Physics).
3. Quantum theory. I. Title.
QC173.59.S65 B374 2000
530.11 21—dc21 99-044319
9 10
Printed in the United States of America
on acid-free paper
CONTENTS
The Story in a Nutshell
Preface
Acknowledgements
PART 1 THE BIG PICTURE IN SIMPLE TERMS
CHAPTER 1 The Main Puzzles
The Next Revolution in Physics
The Ultimate Things
Getting to Grips with Elusive Time
The Properties of Experienced Time
Newton’s Concepts
Laws and Initial Conditions
Why is the Universe so Special?
CHAPTER 2 Time Capsules
The Physical World and Consciousness
Time Without Time
Time Capsules
Examples of Time Capsules
CHAPTER 3 A Timeless World
First Outline
The Crisis of Time
The Ultimate Arena
Is Motion Real?
The Big Picture
PART 2 THE INVISIBLE FRAMEWORK AND THE
ULTIMATE ARENA
CHAPTER 4 Alternative Frameworks
Absolute or Relative Motion?
An Alternative Arena
CHAPTER 5 Newton’s Evidence
The Aims of Machian Mechanics
Apparent Failure
Space and Spin
Energy
CHAPTER 6 The Two Great Clocks in the Sky
Where is Time?
The First Great Clock
The Inertial Clock
The Second Great Clock
CHAPTER 7 Paths in Platonia
Nature and Exploration
Developing Machian Ideas
Exploring Platonia
PART 3 THE DEEP STRUCTURE OF GENERAL
RELATIVITY
CHAPTER 8 The Bolt from the Blue
Historical Accidents
Background to the Crisis
Einstein and Simultaneity
The Forgotten Aspects of Time
CHAPTER 9 Minkowski the Magician
The New Arena
From Three to Four Dimensions
Are There Nows in Relativity?
CHAPTER 10 The Discovery of General Relativity
Funny Geometry
Einstein’s Way to General Relativity
The Main Advances
The Final Hurdle
General Relativity and Time
CHAPTER 11 General Relativity: The Timeless Picture
The Golden Age of General Relativity
Platonia for Relativity
Best Matching in the New Platonia
Catching up with Einstein
A Summary and the Dilemma
PART 4 QUANTUM MECHANICS AND QUANTUM
COSMOLOGY
CHAPTER 12 The Discovery of Quantum Mechanics
CHAPTER 13 The Lesser Mysteries
Introduction
The Wave Function
Interpreting the Wave Function
States Within States
The Copenhagen Interpretation
Heisenberg’s Uncertainty Principle
The Enigmatic Gem
CHAPTER 14 The Greater Mysteries
Schrödinger’s Vast Arena
Correlations and Entanglement
The EPR Paradox
Bell’s Inequalities
The Many-Worlds Interpretation
A Dualistic Picture
CHAPTER 15 The Rules of Creation
The End of Change
Creation and the Schrödinger Equation
Quantum Mechanics Hovering in Nothing
CHAPTER 16 ‘That Damned Equation’
History and Quantum Cosmology
A Simple-Minded Approach
‘That Damned Equation’
PART 5 HISTORY IN THE TIMELESS UNIVERSE
CHAPTER 17 The Philosophy of Timelessness
CHAPTER 18 Static Dynamics and Time Capsules
Dynamics Without Dynamics
Why do we Think the Universe is Expanding?
The Idea of Time Capsules: The Kingfisher
CHAPTER 19 Latent Histories and Wave Packets
Smooth Waves and Choppy Seas
History Without History
Airy Nothing and a Local Habitation
Schrödinger’s Heroic Failure
CHAPTER 20 The Creation of Records
History and Records
The Creation of Records: First Mechanism
The Prerequisites of History
The Improbability of History
The Creation of Records: Second Mechanism
CHAPTER 21 The Many-Instants Interpretation
Many Histories in One Universe
Bell’s ‘Many-Worlds’ Interpretation
The Many-Instants Interpretation
CHAPTER 22 The Emergence of Time and its Arrow
Causality in Quantum Cosmology
Soccer in the Matterhorn
Timeless Descriptions of Dynamics
A Quantum Origin of the Universe?
Vision of a Timeless Universe
A Weil-Ordered Cosmos?
EPILOGUE Life Without Time
Notes
Further Reading
Bibliography
Index
LIST OF DISPLAY ITEMS
BOXES
1 The Great Revolutions in Physics
2 The Two Big Mysteries
3 Possible Platonias
4 Centre of Mass
5 The Galilean Relativity Principle
6 The Equation of Time
7 Tait’s Inertial Clock
8 Intrinsic Difference and Best Matching
9 Relativity in One Diagram and 211 Words
10 The Impossible Becomes Possible
11 The Two-Slit Experiment
12 Entangled States
13 How Creation Works
14 The Semiclassical Approach
15 Static Wave Packets
ILLUSTRATION